Research On Direct Instantaneous Torque Control Strategy Of Switched Reluctance Motor

Switched reluctance motor has the characteristics of high output efficiency,wide speed regulation range,low cost and flexible control mode.It is used in aerospace,textile machinery,electric vehicles,elevator drive and other fields.However,due to the unique double salient pole structure and the pulsed power supply mode of the switched reluctance motor,the torque ripple,noise and vibration of the motor are relatively large.Torque ripple is especially noticeable during commutation,and the direct instantaneous torque control strategy limits the instantaneous torque of the motor to a certain range.Therefore.it is of great theoretical significance and practical value to study the direct instantaneous torque control strategy of switched reluctance motor.Switched reluctance motors have severe magnetic saturation,making it difficult to establish parametric,analytical mathematical models.In order to make the control of the switched reluctance motor more precise,it is necessary to establish a nonlinear mathematical model of the switched reluctance motor,which requires accurate motor flux-rotor position-current characteristic data.Several methods for obtaining the flux linkage data of switched reluctance motor are compared and analyzed.Considering the practicability and accuracy,the flux linkage data of the switched reluctance motor is obtained by the method of partition analysis and fitting based on the special position magnetic characteristic curve.Furthermore,the torque-rotor position-current characteristic table of the motor is obtained.Based on this,a nonlinear model of the switched reluctance motor is established.The existing control stratugy is compared and analyzed,and the direct instantaneous torque control strategy is selected to realize the control of the motor.This method can achieve good control of the torque.However,the phase current of the motor is uncontrollable,there will be a large current spike in the commutation area,and there is a large torque fluctuation.In order to reduce the torque ripple and optimize the phase current waveform,the particle group algorithm is used to optimize the opening angle and the closing angle to obtain the optimal combination of the opening angle and the closing angle.In order to improve the response speed and robustness of the system,a fuzzy speed controller is designed.The simulation model of direct transient torque control system of switched reluctance motor is established in Matlab environment.The simulation results of the control method are compared with the simulation results of traditional direct instantaneous torque control.The results show that the method used can significantly reduce the torque ripple and also effectively reduce the peak of the phasecurrent.Takingathree-phase 12/8-pole SR motor as the research object,TI's TMS320F28335DSP is used as the control chip,the hardware experimental platform of switched reluctance motor was built,and the software program was designed and written with CCS7.4 as the software platform.The experimental results show that the particle swarm optimization algorithm is used to optimize the opening and closing angle combined with the double closed loop control method to reduce the torque fluctuation range and improve the performance index of the switched reluctance motor.